Problem: Emily is 4 times as old as Stephanie and is also 24 years older than Stephanie. How old is Stephanie?
Solution: We can use the given information to write down two equations that describe the ages of Emily and Stephanie. Let Emily's current age be $e$ and Stephanie's current age be $s$ $e = 4s$ $e = s + 24$ Now we have two independent equations, and we can solve for our two unknowns. Since we are looking for $s$ , and both of our equations have $e$ alone on one side, this is a convenient time to use elimination. Subtracting the second equation from the first equation, we get: $0 =$ $4s$ $-$ $ (s + 24)$ which combines the information about $s$ from both of our original equations. Solving for $s$ , we get: $3 s = 24$ $s = 8$.